Filepond type validation doesn't work for doc and docx files on several windows platforms

[JohnPaul97]

Source code:

fileValidateTypeDetectType: (file, type) => new Promise((resolve, reject) => {
     
     var startOfFile = initObject.mediaType === videoMediaType
       ? file.slice(0, 12)
       : file.slice(0, 4);

     var reader = new FileReader();

     reader.readAsArrayBuffer(startOfFile);
     reader.onload = function () {
       switch (initObject.mediaType) {
         case imageMediaType:
           validateImageFormat(resolve, reject, type, reader.result);
           return;
         case videoMediaType:
           validateVideoFormat(resolve, reject, type, reader.result);
           return;
         case documentMediaType:
           validateDocumentFormat(resolve, reject, type, reader.result);
           return;
         default:
           reject(type);
       }
     };
   })

I process for every uploaded file its signature in order to assure type correctness before any call to backed. The problem appears for all doc/docx files on several windows os' (I tested with win10 and win8 several distributions and as browsers I used chrome/mozilla/edge, the problem persists for all). I debugged a little and I found out that internally file pond perform some type validations on its own (despite the fact that I implemented this function above) and it uses the type autodetected by the browser, which in my case was the empty string. As a result, the file type validation doesn't reject the type from my code but from internal call. What should I do in order to be able to upload doc/docx? I read in a previous topic that someone mentioned that office package may be needed in order to help browser correctly detect file types but this is not an option.

[rikschennink]

setting acceptedFileTypes to for example doc/docx and then returning doc/docx from the fileValidateTypeDetectType should work.